The double wire binding is a double wire ring that will be bent in advance. The ring is worn on the square hole or hole in advance on the scattered page, and the metal ring is pressed by the special equipment to complete the binding. Double ring is the first choice of ring binding, beautiful appearance, strong and durable, can accommodate different materials, different shapes of pages, suitable for the thickness of 1 inches of books, widely used in technical manuals, cooking books, product design manuals and other products. The disadvantage is that after the metal ring is pressed, no more pages can be added.

There are two types of double coil binding: 3: 1 and 2: 1.

3: 1 refers to the number of holes distributed on the length of each inch, which is 3.

2: 1 means 2 holes per inch in length, and the metal ring has better durability and stability.